# Copyright (c) 2021, NVIDIA CORPORATION.  All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

import sys
from unicodedata import category

from nemo_text_processing.text_normalization.en.graph_utils import NEMO_NOT_SPACE, NEMO_SIGMA, GraphFst

try:
    import pynini
    from pynini.lib import pynutil
    from pynini.examples import plurals

    PYNINI_AVAILABLE = True
except (ModuleNotFoundError, ImportError):
    PYNINI_AVAILABLE = False


class PunctuationFst(GraphFst):
    """
    Finite state transducer for classifying punctuation
        e.g. a, -> tokens { name: "a" } tokens { name: "," }

    Args:
        deterministic: if True will provide a single transduction option,
            for False multiple transduction are generated (used for audio-based normalization)

    """

    def __init__(self, deterministic: bool = True):
        super().__init__(name="punctuation", kind="classify", deterministic=deterministic)
        s = "!#%&\'()*+,-./:;<=>?@^_`{|}~\""

        punct_unicode = [
            chr(i) for i in range(sys.maxunicode) if category(chr(i)).startswith("P") and chr(i) not in "[]"
        ]
        punct = pynini.union(*s) | pynini.union(*punct_unicode)

        emphasis = (
            pynini.accep("<")
            + (
                (pynini.closure(NEMO_NOT_SPACE - pynini.union("<", ">"), 1) + pynini.closure(pynini.accep("/"), 0, 1))
                | (pynini.accep("/") + pynini.closure(NEMO_NOT_SPACE - pynini.union("<", ">"), 1))
            )
            + pynini.accep(">")
        )
        punct = plurals._priority_union(emphasis, punct, NEMO_SIGMA)

        self.graph = punct
        self.fst = (pynutil.insert("name: \"") + self.graph + pynutil.insert("\"")).optimize()
